1. Field of the Invention
The present invention relates to a package inspection device for inspecting bunch wound yarn wound onto a take up tube.
2. Prior Art
The package wound by the take up winder is bunch wound on the take up tube and then formed into a package.
In recent years, instead of cardboard tubes, resin tubes are being used in take up tubes and they are often brightly coloured, for example, yellow or pink.
Various means of package inspection take place to see if the package has been correctly wound or not.
In conventional inspection of bunch wound yarn, a white light irradiates the bunch wound yarn which is scanned by a CCD camera, and the bunch wound yarn is inspected by means of image processing.
However, because the take up tube is brightly coloured as mentioned above, if the take up tube and the bunch wound yarn are scanned by the CCD camera, it is difficult to show a clear contrast between them. Further, because the take up tube contains a number of small lumps or protuberances which stop the yarn slipping easily, even when there is no bunch wound yarn, it is easy to detect these small protuberances as the bunch wound yarn by mistake, so that inspection cannot be done accurately.
For this reason, the present invention seeks to overcome the above problems and to provide a package inspection device which is capable of accurately distinguishing bunch wound yarn and the take up tube for bunch wound yarn inspection.